Science Fiction and Fact

1934
"Sidewise in Time"
While physicists contemplate waveform collapse, author William Fitzgerald Jenkins writes of parallel worlds under the pen name Murray Leinster. In the story "Sidewise in Time," a mathematics professor named Minott predicts that patches of parallel universes—worlds where human history unfolded differently—will start to tear through into our reality. When that actually happens, Minott leads a band of students on an adventure across the parallel worlds, hoping to locate and rule a world that lacks sophisticated technology. "Sidewise in Time" isn't the first story to feature parallel worlds, but it does bring the concept to a pulp science fiction audience when the story is published in Astounding Stories in 1934.